Robotic Resection of Colonic Medullary Carcinoma: A Case Report.

Colorectal medullary carcinoma (MC) is a rare and distinct subtype of colorectal cancer associated with mismatch repair (MMR) deficiency with the loss of MLH1 and PMS2 genes. Due to its rare incidence and atypical histopathological features, MC is often misclassified as a poorly differentiated adenocarcinoma. We present the case of an 87-year-old elderly male with iron deficiency anemia and a right-sided abdominal mass. Initial colonoscopy biopsy reported a poorly differentiated adenocarcinoma, but subsequent surgical resection confirmed MC. The patient elected to undergo a right hemicolectomy via a robotic-assisted approach. Although the potential oncologic benefit of robotic surgery remains uncertain, it was chosen in this case due to the patient's preference for a minimally invasive procedure, his advanced age, and the tumor's relatively large size. No adjuvant therapy was recommended after a multidisciplinary review given the tumor's MMR deficiency and absence of regional lymph node metastasis. This report highlights the diagnostic challenges of MC and the potential benefits of a robotic approach for MC resections in an elderly patient.